Which of the following conditions is NOT classified as a secondary lesion?

In dermatology, secondary lesions result from changes in primary lesions or are the consequence of external factors such as infection, injury, or inflammation. Primary lesions often represent the initial skin condition and include structures like macules, papules, and vesicles, which arise directly from a pathological process.

A vesicle, which is a small fluid-filled blister, is classified as a primary lesion. It forms without a prior skin condition but can become a secondary lesion if it ruptures and leads to further complications, such as crusting or infection.

On the other hand, conditions like psoriasis represent a chronic skin disorder characterized by red, inflamed patches covered with silvery scales, and are seen as primary lesions. The fissure and ulcer are secondary lesions that emerge as a consequence of complications such as chronic irritation or constant pressure, where the skin breaks down.

Thus, among the choices, the vesicle does not belong to the category of secondary lesions, clarifying its classification and role in skin conditions.